Your Wi-Fi light is green, YouTube plays, WhatsApp works, and yet one website refuses to open. Or it opens on your phone's mobile data but not on home broadband. This is one of the most common complaints on Indian fiber and broadband connections, and it is usually fixable in a few minutes once you work out which layer is failing.
This guide is for home users and small-business owners on any Indian ISP, including Jio, Airtel and regional providers. SiteDownCheck is not affiliated with any ISP. Router menus and ISP policies differ and change, so treat the screens described here as typical rather than exact.
Step 1: Is the site down for everyone?
Before you change anything, find out whether the problem is the website, your connection, or something in between. Run the address through Down From Where, which checks from several locations, and the Website Health Check.
- Down everywhere: the site itself has a problem. Wait, or follow the site's official status or social channel. Nothing on your router will help. Our guide website down for everyone or just me covers this split in detail.
- Up elsewhere, down for you: the problem is on your network, your device, or your ISP's path to that site. Continue below.
Step 2: Read the exact error
The wording of the browser error points at the failing layer.
| What you see | Usual meaning |
|---|---|
DNS_PROBE_FINISHED_NXDOMAIN or "server IP address could not be found" | Your resolver could not find the name. See DNS_PROBE_FINISHED_NXDOMAIN. |
ERR_NAME_NOT_RESOLVED | Same family: name lookup failed. See ERR_NAME_NOT_RESOLVED. |
ERR_CONNECTION_TIMED_OUT | The name resolved but packets are not getting through or back. |
ERR_CONNECTION_RESET or ERR_CONNECTION_CLOSED | A connection was made then cut. See ERR_CONNECTION_CLOSED. |
| Certificate or "connection is not private" warning | Often wrong date/time on the device, or something interfering. See your connection is not private. |
| Page loads for a long time, then partly | Slow path, congestion, or a heavy third-party script. |
Step 3: Fix a DNS problem (most common)
Your ISP gives your router a DNS resolver, which turns example.com into an IP address. If that resolver is slow, overloaded, or has a stale or wrong answer for one site, that site fails while others work.
Test it from a terminal:
nslookup example.com
nslookup example.com 8.8.8.8
nslookup example.com 1.1.1.1If your default resolver fails or returns a different answer than the public resolvers, DNS is the issue. Also check the name with our DNS Checker to see what the world sees.
Quick fixes, in order:
- Flush the local cache. On Windows run
ipconfig /flushdns. On macOS runsudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder. On Linux with systemd-resolved runresolvectl flush-caches. - Restart the router, wait a full minute, and try again.
- Switch the DNS server on your device or router to a public resolver. Step-by-step instructions are in change DNS on Indian ISPs and routers.
If the site works after a DNS change, your ISP's resolver was the weak link. Keep the new setting.
Step 4: Suspect IPv6 when only some sites fail
Many Indian ISPs deliver IPv6 along with IPv4. When a site publishes an IPv6 address but the path to it is broken or slow, your browser may try IPv6 first and stall before falling back. Symptoms: one site hangs, others are fine, and the same site opens on another network.
Test both protocols:
curl -4 -I https://example.com/ --max-time 15
curl -6 -I https://example.com/ --max-time 15If the -4 request works and -6 hangs or fails, you have an IPv6 path problem. You can confirm what addresses your connection uses with What Is My IP. Options are to turn off IPv6 on the router's LAN or WAN side (if the menu allows it), or ask the ISP to look at the route. Disabling IPv6 is a diagnostic step; note what you changed so you can reverse it. Background reading: IPv6 and IPv4.
Step 5: Rule out your own device and browser
- Try another browser or a private window to exclude extensions and cached redirects.
- Check the date and time. A device clock that is far off breaks HTTPS.
- Turn off any VPN, proxy or "secure DNS" setting temporarily and test again, then restore your preferred setting. A misconfigured proxy gives errors like ERR_PROXY_CONNECTION_FAILED.
- Try a second device on the same Wi-Fi. If every device fails, look at the router and ISP. If one device fails, look at that device.
- Clear the site's cookies and cache for the domain only.
Step 6: Is the ISP route the problem?
Sometimes the name resolves fine and the site is up globally, yet your connection to that site's servers is poor. Peering between networks can degrade, and routes change. Use traceroute to see where packets stop or slow:
tracert example.com (Windows)
traceroute example.com (macOS, Linux)A few * lines in the middle are common and not always a fault. What matters is whether the trace dies at a hop and never reaches the destination, or shows a sharp jump in latency early in the path. Save the output and the time. It is useful evidence when you contact support. Read more in traceroute and latency.
Some connections also use carrier-grade NAT, where many customers share one public IP address. This can matter if a site's firewall blocks or rate-limits that shared address. See CGNAT. If a business service rejects you only on home broadband, ask the ISP about a public static IP and check yours with What Is My IP.
Step 7: Consider whether access is restricted
A site that never opens on certain ISPs, while resolving normally elsewhere, may be restricted at the network level. That is a legal and policy matter and not a fault to troubleshoot with settings. Our guide website blocked in India: how to tell explains how to distinguish a block from an outage so you know whether to wait, ask the site owner, or contact your ISP.
Contacting your ISP effectively
If the steps above point to the ISP, a clear report gets faster results than "internet not working".
- Your account or customer ID and the connection type.
- The exact site address and the exact browser error.
- Results of
nslookupwith the default resolver and with a public resolver. - The traceroute output with time of test.
- Whether other networks (mobile data) open the site.
- Reference number of the complaint. Write it down and quote it on follow-up.
Use only the official helpline, app or website of your provider. Be careful of search results that show fake "customer care" numbers, and never share OTPs, UPI PINs or remote-control app access with someone who calls claiming to fix your internet.
Next steps
- Change DNS on Indian ISPs and routers
- Website down for everyone or just me
- DNS Checker to compare answers worldwide
- Down From Where to see which locations can reach a site
- Website blocked in India: how to tell
FAQ
Why does a website open on mobile data but not on my home broadband?
The two networks use different DNS resolvers and routes. A stale DNS answer, a broken IPv6 path, or a router setting is the usual cause. Test with a public DNS server and compare IPv4 and IPv6.
Will restarting my router really help?
Often yes, because it renews the connection, refreshes the DHCP lease and clears the router's DNS cache. Wait about a minute before powering it back on, and test one site before changing other settings.
Is it safe to use a public DNS server on my router?
Public resolvers from large providers are widely used, but they see your lookups, so read their privacy policies. Your ISP's resolver sees them as well. Choose one you are comfortable with.
How long should I wait before calling my ISP?
If a second network can open the site but yours cannot, and a DNS change and router restart do not help, report it with your test results. If the site is down from every location, the fault is not with your ISP.
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This page is general information written by our editorial team and updated when documentation changes. Servers and providers differ, so test changes safely first. See our editorial policy and disclaimer.